Powder-proof bank-lock



UNITED STATES PATENT OFFIOE.

WM. HALL, OF BOSTON, MASSACHUSETTS.

POWDER-PROOF BANK-LOCK.

Specification of Letters Patent No. 8,257, dated July 29, 1851.

To all whom t may concern:

Be it known that I, WILLIAM HALL, of Boston, in the county of Suffolkand State of Massachusetts, have invented certain new and usefulImprovements in Locks for Bank-Vaults, Safes, &c., and that thefollowing description, taken in connection with the accompanyingdrawings, hereinafter referred to, forms a full and exact specificationof the same, wherein I have set forth the nature and principles of mysaid improvements by which my inventionmay be distinguished from othersof a similar class, together with such parts as I claim and desire tohave secured to me by Letters Patent.

The figures of the accompanying plate of drawings, represent myimprovements.

Figure l is a plan of a lock, combining my improvements, with thecovering plate removed, so as to expose the operative part-s to view.Fig. 2 is adetail view of the central part of the lock, with theaforesaid plate in its place. Fig. 8 is also a detail view of said part,with said plate removed, and also a sliding plate, hereinafter referredto detached. Fig. 4 is a sectional view taken in the plane of the line AB, Fig. 2, and Fig. 5 is a sectional view, taken in the plane of theline C D, Fig. 2.

, The essential features of my improvements consist in providing amovable slide or follower, arranged in a continuation of the key holerecess, which moves after the key during the process of locking andunlocking, filling up the entire recess; so as to prevent any feelingof, or tampering with the tumblers, or the introducing and conlining anypowder in the key-hole, for blowing up the lock; also in providing atransverse slide, which traverses in a groove, formed at right angles tothe recess formed for the key, for cutting off all communication withthe tumblers, when the key-hole is open. Having these improvements, thelock does not differ substantially in its elementary principles, fromthat which is described in the schedule, annexed to the patent, grantedto me on the first day of August, in the year 1848, for a powder prooflock.7

a ci a, &c., in the several drawings, represent the casing of the lock.b ZJ b are three bolts, attached to one vertical bar c c, from thecenter of, and at right angles to which extends backward the arm l al,the whole forming a bolt frame, as I shall term it. A

stud c, is secured in same proper position on this arm CZ CZ, andengages with the several tumblers f f, in the usual way, said tumblershaving each a throat g, all of which throatsI have to be brought intoapposition with each other, to permit the stud e to engage with, or bedisengaged from said tumbl-ers, in the process of locking and unlocking.The bolt frame is thrown forward and back, by means of the cam 72 onpart of the lower turning arbor z', Fig. 3, which cam engages with anotch 7c, in the piece Z, depending from the underside of the arm l d,and the turning of said arbor, is effected by any proper kind of handle,having a square socket, applied to its top.

The tumblers f f f, are provided with springs m m arranged as shown inFigs. l and 3, and they are moved by the key operating on the slidingpins o1, fn., which play in proper sockets, in the metallic block o 0,and the heads of which bear against the undersides of said tumblers.

The key p is formed with such inequalities on the edge which moves thepins n n, as to bring the mouths of the tumbler-s into apposition witheach other, as before eX- plained. The recess for the insertion of thekey, is formed by .making a deep groove in the brass block 0 0, at g Q.This recess is extended of the same depth, through the length 7 r, andin the extension of said recess, is inserted the follower s, which is ofthe same depth as the groove, and the upper edge of which abuts againstthe under edge of the key, and when the key moves, this follower moveswith it, and fills up the recess, so as to prevent all tampering withthe tumblers, and also the confining of any powder in the recess. Thisfollower is connected to one end of the bent lever t t, which has afulcrum at u, said end of said lever being fitted in a notch in saidfollower, as shown in Fig. 3. This lever is moved, so as to move saidfollower, and consequently, the key, by the surface of the cam o, on thearbor z', above the cam 71 which cam v lifts said lever, whenever it isbrought to bear against its underside; the spring y' pressing it downagain, whenever the pressure of said cam is removed.

It now only remains for me to describe the transverse slide for cuttingoff all communication with the pins n n, or tumblers, when the key-holeis open, and the key is in the lock.

a a is a sliding plate, which its over the key recess in the block 0 0,and has a rectangular hole b', Fig. 4, through which the key is insertedin its place; on the underside of this plate, is the vertical plate c c,Fig. 5, which tits into, and fills up the transverse groove d, formed inthe block 0 0. The plate c c Fig. 5, has a slot e in it, which permitsthe play, or sliding through of the key, at the proper time, but whenthe key-hole is open, and the key is in its place, the solid part of theplate c c obstructs the passage of the key, and cuts off allcommunication with the tumblers.

The plate a a is moved forward and back by means of the cam j, on thearbor z', which works in the eccentric shaped slot g g" of said plate,in a manner which will be understood by inspection of Fig. l.

In locks when the sliding plate a a, is used, the key hole should passthrough the lock, in order that if powder is inserted, it may blow outof the hole, without injuring the lock.

make a powder proof lock, with tumblers which cannot be. reached byapick, and whose slide cannot be blown off, so as t0 secure access tothe t-umblers.

2. I also c aim the combination with the plate a a', of the transversesliding vertical slot-ted plate .0 0, which jointly cut of allcommunication with the tumblers, in every position of the bolt.

' WM. HALL.

Vitnesses:

STEPHEN SMITH, EZRA LINCOLN.

